STANDARD TERMINOLOGY

In order to make communications between the people involved with HASKEL pumps less confusing, a "standard" parts description is needed. Part numbers and model numbers are adequate for pump assemblies, but the individual areas of the pump involved in trouble-shooting need "generic" descriptions applicable to all models in order to simplify the task of communication. The following descriptive names are recommended to facilitate transfer of information on pump problems.

AIR DRIVE

The low pressure air driven section of the pump which moves the air drive piston alternately in opposite directions to power the hydraulic section for generation of flow and pressure.

CYCLE

One complete back and forth motion of the air drive piston. There are two strokes to a cycle.

STROKE

The travel of the air drive piston from one end cap to the opposite end cap. A stroke is one-half of a cycle.

VALVE END CAP

The air drive end cap containing the cycling valve and the pilot fill valve.

PILOT VENT END CAP

The air drive end cap (opposite to the valve end cap) which contains the pilot vent valve.

AIR BARREL

The cylindrical section of the air drive, between the two air caps, that guides the air piston and provides a surface for the piston seal.

AIR PISTON

The low pressure piston in the air drive that connects to the plunger/piston and provides the reciprocating (back and forth) motion needed for pumping fluid to produce pressure and flow.

PILOT FILL VALVE

The normally closed pilot valve, located in the valve end cap that pressurizes the pilot chamber when actuated open by the air piston.

PILOT VENT VALVE

The normally closed pilot valve, located in the pilot vent end cap, that vents the pilot chamber when actuated open by the air piston.

AIR CYCLING VALVE

The valve assembly used to direct the flow of air alternately to one side of the air piston and then the other, to produce the reciprocating (back and forth) motion needed to make the pump function.

SLEEVE

The tubular portion of the cycling valve that contains the "porting" holes to direct the air to its proper destination, based on the position of the spool. This sleeve is sealed against "lands" in the valve end cap to partition the flow passages.

SPOOL

The moving portion of the air cycling valve that is controlled by the pilot valves pressurizing and venting the pilot chamber at one end of the spool. The "O" rings on the spool "partition" the flow to direct it to the proper passages in the sleeve to cycle the air piston.

FLOW TUBE

The flow tube routes the drive air from the valve end cap to the opposite end cap to provide pressure for the stroke towards the valve end cap. It also provides the path for venting the drive air from that side of the piston at the end of the stroke.

PILOT TUBE

The pilot tube connects the pilot chamber to the pilot vent end cap. When the air piston actuates the pilot vent valve open, it vents the pressure in the pilot chamber and shifts position of the cycling valve to reverse the direction of the air drive piston.

PUMPING SECTION

The section containing the hydraulic body, plunger/piston, seal package and check valves. All parts of this section are exposed to the pumped fluid. Therefore, all materials used must be compatible.

HYDRAULIC BODY

The high pressure structural section of the pump. It contains the high pressure seal package and check valves.

PLUNGER/PISTON

The part, mechanically connected to the air piston that moves back and forth in the hydraulic body of the pump to produce pressure and flow.

HIGH PRESSURE SEAL

The plunger, piston, or rod seal in the hydraulic body that seals the pressure to contain the pumped fluid. This seal may be a single part or a combination of parts, and is installed with bearings and backups as required to provide a "seal package" capable of resisting the pressure generated.

INLET CHECK VALVE

The check valve, located in the hydraulic body that permits entrance of the fluid on the "suction" stroke, and closes to trap fluid on the "pumping" stroke.

OUTLET CHECK VALVE

The check valve, located in the hydraulic body, that permits fluid to go into the downstream system during a "pumping" stroke and closes to prevent return of the system fluid during the "suction" stroke.

FLOW

The amount of fluid pumped into the downstream system. The amount is calculated by " flow= (displacement per cycle) * (cycles per minute)" and is usually measured in "cubic inches per minute" (CIM), or "gallons per minute" (GPM).

ACTUAL PRESSURE RATIO

The number obtained by dividing the area of the air barrel I.D. by the cross-sectional area of the plunger/piston exposed to the fluid.

NOMINAL PRESSURE RATIO

The "Actual Pressure Ratio" multiplied by a factor to account for losses due to internal friction in the pump. This number is normally used to determine maximum attainable pressure. The friction factor normally used for pumping non-lubricating fluids is .88 (12% friction). For lubricating fluids, it will be a lower percentage, and the stall pressure will probably exceed the pressure calculated.

MAXIMUM PRESSURE

Since the pump is a "ratio" device, its maximum pressure depend on the air drive pressure available and the "nominal pump ratio". Multiplying the nominal ratio by the air drive pressure available will give a close estimate of the maximum pressure. It will vary a small amount due to the frictional characteristics of the pumped fluid.

DISTANCE PIECE

A section inserted between the air drive and the hydraulic body to separate them at a distance greater than the travel (stroke) of the plunger/piston. The distance piece is vented, so that any leakage from the fluid end will not be able to contaminate the air drive, and vice versa. Many times, the fluid pumped is not compatible with the air drive "O" rings, and could cause swelling which would result in excessive friction and stoppage. When critical fluids are used, it also protects the hydraulic section from air drive contaminants such as oil or moisture. The distance piece is also used when the fluids pumped are at temperature that could adversely affect the air drive seals. It provides a distance for heat transfer to minimize the temperature differential.

SINGLE-ACTING PUMP

A pump that takes in fluid on one stroke of the cycle and discharges it on the other stroke.

DOUBLE-ACTING PUMP

A pump designed to discharge fluid on both strokes of the cycle. Depending on the check valve arrangement, the input (suction) of pumped fluid can be on both strokes or only one.

SINGLE ENDED PUMP

A pump which has the pumping section only on one end of the air drive. It may be single acting (as in the "A" and "D" series) or double acting (as in the "G" series)

DOUBLE ENDED PUMP

A pump having pumping sections on both ends of the air drive. It may be "double acting" (as in the GW-12) or "compound" (as in the AWD-11/225).